Generally, in transmission systems of electrical signals, there are roughly two systems, that of unbalanced transmission and balanced transmission. Unbalanced transmission is a system that transmits an electrical signal using a single transmission line. Moreover, balanced transmission is a system that, as in Patent Document 1, for example, converts the electrical signal into a pair of transmission signals (differential signals) of mutually opposite phases and transmits these signals using a pair of transmission lines.
The two systems greatly differ in how they are influenced by noise received during transmission. For example, in unbalanced transmission, when the transmission line receives the noise from the outside, a noise component is superimposed on the electrical signal during transmission. Because of this, the influence of the noise received from the outside cannot be avoided.
Meanwhile, in balanced transmission, each noise component is removed when the pair of transmission signals is decoded into an electrical signal of a single phase because noise signals of identical phases and identical amplitudes are normally superimposed on each transmission signal even if the pair of transmission lines receives the noise from the outside. Therefore, the influence of the noise received from the outside can be avoided. Because of this, balanced transmission is often used in a high-speed communication systems using a high-speed communication interface, such as <LVDS, HDMI>, and in communication systems using high-frequency signals.